1. Field of the Invention
This invention concerns a method and apparatus for identifying objects by securing different code generating electrical circuits, such as microelectronic circuits provided on a small chip substrates, on different objects and activating each circuit by means of external energy applied thereto, when it is within range or contact with a source of such energy. The resulting code generated when the microelectronic circuit become activated or energized, is either transmitted by short wave or as electrical signals on a temporarily completed circuit to a computer where it is recorded and either analyzed or applied to effect a control function such as the operation of a mechanical gate, switch or conveyance for the object containing the code generating circuit.
2. Description of the Prior Art
The prior art employed electro-optically scannable printed codes, reflectors, pins for operating limit switches and other scannable recordings, all of which suffered shortcomings due to wear, weathering, switch failure, scanning and reading difficulties, etc. Electro-optical reading systems require suitable alignment and operation of the photoelectric detector or detectors effecting such reading with respect to the printed or reflective codes disposed on the objects passing the reading station. Such systems also require unobstructed pathways between the reader and the codes disposed on the objects. Weather conditions also affect the ability to electro-optically read codes. Limit switches are subject to malfunction and wear. Magnetic record reading systems generally require alignment and proper contact between magnetic transducer and the recording surface.